Whole lake responses to low level copper sulfate treatment

The impact of three low level copper sulfate applications to Cazenovia Lake, New York, was assessed through a high frequency monitoring program. Monitored parameters included: (1) filtered and total copper; (2) phytoplankton identification and enumeration; (3) chlorophyll-a, (4) in situ¹⁴C assimilation; (5) bacteria numbers; (6) zooplankton identification and enumeration, (7) macrophyte nutrient status and (8) filtered reactive and total phosphorus.The low level application caused only small increases (maximum of 5 μg/l) of short duration (2–5 days) in filtered copper. The treatments failed to induce effective algicidal action in the target phytoplankton populations of the lake, but they did induce short term stress and alterations in the natural seasonal succession processes within these populations. No definitive responses in the zooplankton, submerged macrophytes or water column phosphorus levels were noted. Dramatic reductions in the water column bacteria occurred immediately following each treatment, indicating direct negative impact. Phytoplankton and bacteria populations recovered within 1 week and several days, respectively.     

Time-action characteristics of regular and NPH insulin in insulin-treated diabetics

The time course of action of regular and NPH insulins injected sc was studied in 15 insulin-treated diabetics over a 24-h period during which they received a constant infusion of glucose. The blood glucose began to decline in 1.2 +/- 0.1 h (range, 0.5--2) and reached its nadir in 5.7 +/- 0.3 h (range, 4--8) after the sc injection of regular insulin. The peak effect of regular insulin usually persisted for several hours, and the total duration of action was 16.2 +/- 1.1 h (range, 9--24). Both the time of peak effect and the total duration of action were considerably prolonged compared to data provided in standard textbooks. Free insulin increased to a peak in 2.7 +/- 0.3 h (range, 1--4) after regular insulin injection and then returned to baseline by 8.8 +/- 0.96 h. Subcutaneous injection of NPH insulin decreased the blood glucose by 2.4 +/- 0.5 h (range, 1--7), with a maximal effect at 11.0 +/- 1.4 h (range, 5--19). The total duration of effect on blood glucose was 25.1 +/- 0.7 h (range, 20--29). These values are similar to those in standard textbooks. Although the total insulin levels increased after the injection of NPH insulin, there was very little if any elevation in free insulin. Recognition of the prolonged effect of regular insulin is important in establishing an insulin treatment regime for diabetic patients.     

Chlorpropamide-induced thrombocytopenia

Thrombocytopenia is a rare complication of chlorpropamide therapy. An immunological mechanism is generally held responsible, but has never previously been proved. In the present case the existence of such a mechanism has been established.     

Cooled broadband parametric amplifier at 4 GHz

A low-noise parametric amplifier, giving 10dB gain from 3.7 to 4.2GHz, is described. The amplifier is cooled to about 20°K using a closed-cycle refrigerator.     

Measurement of extracellular fluid volume in patients on maintenance hemodialysis

Angiosarcoma of the breast, a rare tumor with very poor prognosis and insidious early manifestations, frequently is far advanced when first detected clinically. The clinical and pathologic changes in two women with primary, unilateral angiosarcoma of the breast are reviewed and the results are compared with 46 cases already published in the literature. Both patients were middle aged with symptoms for approximately 6 months prior to operation. Both frozen section reports were benign and only called malignant on permanent section. Microscopically the tumors were composed of varying sized, tortuous, elongated vascular channels. The operation varied--a modified radical and a simple mastectomy--and both patients are free from disease 4 and 2 years following operation. It is considered that, in view of the proclivity of this tumor for hematogenous metastases, an axillary dissection may not be justified.     

Release of microquantities of cyproterone acetate from subcutaneous silastic capsules: failure to produce an antifertility effect

Plasma testosterone profiles were determined by taking frequent blood samples at intervals from birth to 21 months of age from rams reared in isolation, in an all-male group and in a mixed-sex group. The testosterone pattern was not modified by these different social environments. The ability of the ram to copulate when first exposed to an oestrous ewe, apparently a maturational process, was also independent of social rearing. At birth plasma testosterone levels were detectable but low, they were higher at 10 and 16 weeks of age and showed a marked rise by 26 weeks, coincident with the time of puberty. Depressive effects of season on testosterone profiles occurred during the 2nd year of life but not the 1st year.     

Hemodynamic effects of dobutamine after cardiopulmonary bypass in children

The synthetic inotropic agent, dobutamine, has reportedly increased cardiac output in adults after cardiopulmonary bypass with minimal side effects. Its use in children, after surgical correction of congenital heart disease, was tested by infusing the drug at 1, 4, 7, and 10 micrograms/kg x min in 11 children. While significant increases in cardiac index above control (23, 23, and 16% at 4, 7, and 10 micrograms/kg x min, respectively) were observed, this was achieved at the expense of significant increases in heart rate (15, 24, and 10%). This increase in heart rate (47% in one child) necessitated discontinuing the infusion in 4 subjects. There were also significant increases in systolic and mean blood pressure with no change in stroke volume or peripheral vascular resistance. The authors conclude that in children, dobutamine is an effective inotropic agent acting principally by stimulating beta 1-receptors in the myocardium producing a predominantly chronotropic effect without significant changes in peripheral vascular resistance. Given the intrinsically higher heart rate of children, the levels of tachycardia produced by the drug in some instances reach unacceptable levels and as such, may make dopabutamine unsuitable for use in children after cardiopulmonary bypass.